i86 



INTRODUCTION TO PLANT GEOGRAPHY 



[chap. 



be added with further exploration ; meanwhile familiar examples 

 of flowering plants belonging to this category are the Purple Saxifrage 

 {Saxifraga oppositifolia agg.) and Edwards's Eutrema [Eutrema 

 edwardsii [see Fig. 46). 



B 



Fig. 47. — Maps showing circumboreal and circumaustral distributions. A, Ribes 

 spp. (Currants and Gooseberries), circumboreal (after Hutchinson), but omitting 

 some arctic stations; B, southern species of Donthonia (Poverty-grasses and Wild 

 Oat-grasses), circumaustral (after Fernald) ; also northern range, but omitting a 

 station in southwestern Greenland. 



(3) Circumboreal (or circumaustral) — distributed around the top 

 (or bottom) of the world in the boreal (or austral^) zone. It seems 

 desirable to separate this category from the circumpolar, though 

 clearly a plant can belong to both, as in the case of the Purple 



^ Beware confusion with the other uses of this word in biogeography. 



